The present invention relates to a heat transfer paper. More particularly, the present invention relates to a heat transfer paper having an enhanced receptivity for images made by wax-based crayons, thermal ribbon printers, impact ribbon or dot-matrix printers, and the like.
In recent years, a significant industry has developed which involves the application of customer-selected designs, messages, illustrations, and the like (referred to collectively hereinafter as "customer-selected graphics") on articles of clothing, such as T-shirts, sweat shirts, and the like. These customer-selected graphics typically are commercially available products tailored for that specific end-use. The graphics typically are printed on a release or transfer paper. They are applied to the article of clothing by means of heat and pressure, after which the release or transfer paper is removed.
Some effort has been directed to allowing customers the opportunity to prepare their own graphics for application to an article of clothing. A significant amount of this effort has been by Donald Hare and is represented by the five U.S. patents described below.
(1) U.S. Pat. No. 4,224,358 relates to a T-shirt coloring kit. More particularly, the patent is directed to a kit and method for applying colored emblems to T-shirts and the like. The kit includes a heat transfer sheet having an outlined pattern thereon and a plurality of colored crayons formed of a heat transferrable material, such as colored wax. The method of transferring a colored emblem to a T-shirt or the like includes the steps of applying the colored wax to the heat transfer sheet, positioning the heat transfer sheet on a T-shirt or the like, and applying a heated instrument to the reverse side of the heat transfer sheet, thereby transferring the colored wax to the T-shirt or the like. The nature of the heat transfer sheet is not specified.
(2) U.S. Pat. No. 4,284,456, a continuation-in-part of the first patent, relates to a method for transferring creative artwork onto fabric. In this case, the transferable pattern is created from a manifold of a heat transfer sheet and a reverse or lift-type copy sheet having a pressure transferable coating of heat transferable material thereon. By generating the pattern or artwork on the obverse face of the transfer sheet with the pressure of a drafting instrument, a heat transferable mirror image pattern is created on the rear surface of the transfer sheet by pressure transfer from the copy sheet. The heat transferable mirror image then can be applied to a T-shirt or other article by heat transfer. Again, the nature of the heat transfer sheet is not specified.
(3) U.S. Pat. No. 4,773,953 describes a method for creating personalized, creative designs or images on a fabric such as a T-shirt or the like through the use of a personal computer system. The method comprises the steps of:
(a) electronically generating an image; PA0 (b) electronically transferring the image to a printer; PA0 (c) printing the image with the aid of the printer on an obverse surface of a transfer sheet, said transfer sheet including a substrate with a first coating thereon transferable therefrom to the fabric by the application of heat or pressure, and a second coating on said first coating, said second coating defining said obverse face and consisting essentially of Singapore Dammar Resin; PA0 (d) positioning the obverse face of the transfer sheet against the fabric; and PA0 (e) applying energy to the rear of the transfer sheet to transfer the image to the fabric. The transfer sheet can be any commercially available transfer sheet consisting of a substrate having a heat transferable coating, wherein the heat transferable coating has been coated with an overcoating of Singapore Dammar Resin. PA0 (a) a flexible cellulosic nonwoven web base sheet having top and bottom surfaces; and PA0 (b) an image-receptive melt-transfer film layer overlaying the top surface of said base sheet, which image-receptive melt-transfer film layer comprises from about 15 to about 80 percent by weight of a film-forming binder and from about 85 to about 20 percent by weight of a powdered thermoplastic polymer, wherein each of said film-forming binder and said powdered thermoplastic polymer melts in the range of from about 65 to about 180 degrees Celsius and said powdered thermoplastic polymer consists of particles which are from about 2 to about 50 micrometers in diameter. PA0 (a) a flexible cellulosic nonwoven web base sheet having top and bottom surfaces; PA0 (b) a melt-transfer film layer overlaying the top surface of said base sheet, which melt transfer film layer comprises a film-forming binder which melts in the range of from about 65 to about 180 degrees Celsius; and PA0 (c) an image-receptive film layer overlaying said melt-transfer film layer, which image-receptive film layer comprises from about 15 to about 80 percent by weight of a binder and from about 85 to about 20 percent by weight of a powdered thermoplastic polymer, wherein each of said film-forming binder and said powdered thermoplastic polymer melts in the range of from about 65 to about 180 degrees Celsius and said powdered thermoplastic polymer consists of particles which are from about 2 to about 50 micrometers in diameter.
(4) U.S. Pat. No. 4,966,815, a division of the immediately preceding patent, describes a transfer sheet for applying a creative design to a fabric. The transfer sheet consists of a substrate, a first coating on the substrate of material which is transferable from the substrate to a receptor surface by the application of heat or pressure, and a second coating on the first coating, the second coating consisting essentially of Singapore Dammar Resin.
(5) U.S. Pat. No. 4,980,224 is a continuation-in-part of U.S. Pat. No. 4,773,953, described above, and an abandoned application. The patent describes a method and transfer sheet for transferring creative and personalized designs onto a T-shirt or similar fabric. The design can be created manually, electronically, or a combination of both using personal computers, video cameras, or electronic photocopiers. The transfer sheet in essence is the transfer sheet of U.S. Pat. No. 4,966,815 with the addition of abrasive particles to the Singapore Dammar Resin coating. The abrasive particles serve to enhance the receptivity of the transfer sheet to various inks and wax-based crayons. The patent specifically mentions the use of white silica sand and sugar as the abrasive particles.
In addition to the foregoing references, several references are known which relate generally to the transfer of an image-bearing laminate to a substrate.
U.S. Pat. No. 4,555,436 to Guertsen et al. relates to a heat transferable laminate. The patent describes an improved release formulation for use in a heat transferable laminate wherein an ink design image is transferred from a carrier to an article by the application of heat to the carrier support. On transfer the release splits from the carrier and forms a protective coating over the transferred design. The improved release is coated onto the carrier as a solvent-based wax release. The release coating then is dried to evaporate the solvent contained therein. The improved release is stated to have the property that its constituents remain in solution down to temperatures approaching ambient temperature. Upon transfer, the release forms a protective coating which may be subjected to hot water. The improved release contains a montan wax, a rosin ester or hydrocarbon resin, a solvent, and ethylene-vinyl acetate copolymer having a low vinyl acetate content. U.S. Pat. No. 4,235,657 to Greenman et al. relates to a melt transfer web. The web is useful for transferring preprinted inked graphic patterns onto natural or synthetic base fabric sheets, as well as other porous, semi-porous, or non-porous material workpieces. The transfer web is comprised of a flexible, heat-stable substrate, preferably a saturated paper having a top surface coated with a first film layer of a given polymer serving as a heat-separable layer, and a second film layer superposed on the first film layer and comprised of another given polymer selected to cooperate with the first film layer to form a laminate having specific adhesion to porous, semi-porous, or non-porous materials when heat softened. The desired pattern or design is printed on the coated surface, i.e., the second film layer.
U.S. Pat. No. 4,863,781 to Kronzer also describes a melt transfer web. In this case, the web has a conformable layer which enables the melt transfer web to be used to transfer print uneven surfaces. In one embodiment, the melt transfer web has a separate conformable layer and a separate release layer. The conformable layer consists of copolymers of ethylene and vinyl acetate or copolymers of ethylene and acrylic acid, which copolymers have a melt index greater than 30. The release layer consists of polyethylene films or ethylene copolymer films. In another embodiment, a single layer of copolymers of ethylene and acrylic acid having a melt index between 100 and 4000 serves as a conformable release layer.
Finally, it may be noted that there are a large number of references which relate to thermal transfer papers. Most of them relate to materials containing or otherwise involving a dye and/or a dye transfer layer, a technology which is quite different from that of the present invention.
Notwithstanding the progress which has been made in recent years in the development of heat transfer papers, there still is a need for an improved heat transfer paper for use in industries based on the application of customer-designed graphics to fabrics. The prior art heat transfer papers either are not particularly well suited for use in transferring customer-designed graphics or they produce stiff, gritty, and/or rubbery images on fabric.